1. Field of the Invention
The present invention relates to a toner resin composition having an excellent balance of properties such as non-offsetting properties, fixation properties, blocking resistance and so on, and typically used in electrophotography and electrostatic printing, and to a process for the preparation thereof.
2. Description of the Related Art
The image forming process in electrophotography and electrostatic printing consists of a developing process wherein a photoelectrically conductive insulating layer is uniformly charged to form an electrical latent image by exposure to light, followed by a visualization of that image by an adhesion of toner to the latent image, a process wherein this visible image is transferred to paper, etc., and a process wherein the image is fixed by heating and pressure.
Thus, in the development process, the toner must have charge properties that allow it to maintain a suitable amount of charge even if changes occur in the surrounding environment (humidity, temperature, etc.) so that it is able to favorably adhere to the electrical latent image. In addition, in the fixation process, the toner must have favorable fixation properties with respect to the paper, etc., and must have non-offsetting properties so that it does not adhere to the heat roller when using a heat roller, etc. for fixation. Moreover, blocking must not occur in the toner during storage in a copier and so on.
Based on these properties, styrene-acrylic resins, polyester resins and so on were used in the prior art.
Nevertheless, although toner comprised of a styrene-acrylic resin demonstrates stable charge properties (moisture resistance) as a result of being minimally effected by the environment during use, its fixation to paper is not adequate. On the other hand, although toner comprised of a polyester resin has a favorable fixation to paper, the moisture resistance thereof is poor. Moreover, it is difficult to properly balance the non-offsetting and fixation properties of these types of resins.